Hitachi, Ltd.

Sadao Masuda

Norio Nakazato

Makoto Nawata

Sachihiro Yoshimatsu

Yasuo Tasaka

Kiyoshi Sasaki

A method for the temperature balancing control of a plurality of heat exchangers wherein, in case of operating the heat exchangers connected in parallel, the temperatures of a medium to-be-heated on the outlet sides of the respective heat exchangers are balanced. According to the method, the temperatures of the same positions of the heat exchangers except for the inlets thereof for the medium to-be-heated are sensed, the respective sensed values are compared with a temperature setting value so as to calculate control signals, all the control signals are subsequently revised so that the maximum value among the control signals may agree with a preset control reference value, and temperature regulation means disposed for the respective heat exchangers are controlled on the basis of the revised control signals.

Method and apparatus for the temperature balancing control of a

This invention relates to an air separation method and apparatus for liquefying and separating feed air into oxygen and nitrogen by use of a single rectification column. The temperature of the feed air, which is liquefied, is reduced to the temperature necessary for the condensation and liquefaction of pure vaporous nitrogen inside the single rectification column and is used to condense and liquefy the pure vaporous nitrogen and vaporize the feed air. After the pressure of the feed air thus vaporized is raised to the pressure necessary for the condensation and liquefaction of the pure vaporous nitrogen inside the single rectification column, the vaporized feed air is introduced into the single rectification column so that pure gaseous nitrogen can be withdrawn from the top of the single rectification column, pure gaseous oxygen from a lower portion of the column and waste gas rich in nitrogen from an intermediate portion of the column. Thus, the present invention makes it possible to carry out air separation with a high rate of recovery of oxygen using a single rectification column.

Growing community of inventors

Kudamatsu, Japan

Sadao Masuda